The primary objective of this study is to compare ultrasound versus nerve stimulator techniques for nerve localization when performing peripheral nerve blocks. Specifically the investigators will be performing Popliteal, Femoral, and Interscalene nerve blocks. The investigators will be looking for differences in 1) time taken to locate the target nerve and inject local anesthetic 2) time from injection of local anesthetic to adequate surgical anesthesia 3) effectiveness of block 4) incidence of vascular puncture 5) incidence of adverse events 6) patient satisfaction.